Die-casting or injection-moulding machines



June 18, 1963 H. EHLERT 3,

DIE-CASTING 0R INJECTION-.MOULDING MACHINES Filed April 11, 1961 2Sheets-Sheet 1 June 18, 1963 H. EHLERT 3,093,863

DIE-CASTING OR INJECTION-MOULDING MACHINES Filed April 11, 1961 2Sheets-Sheet 2 United States Patent 3,093,863 DIE-CASTING 0RINJECTION-MOULDING MACHINES Helmut Ehlert, Monclien-Gladbach,Germany,assignor to Schloemann Aktiengesellschaft, Dusseldorf, Germany FiledApr. 11, 1961, Ser. No. 102,152 Claims priority, application GermanyApr. 28, 1960 7 Claims. (Cl. 18-30) This invention relates to adie'cas-ting or injection moulding machine, suitable for the productionof moulded bodies, particularly from thermoplastic synthetic substances,comprising a stationary mould-carrier plate for the accommodation of onemould member, and, for the accommodation of the other mould member, amovable mould-carrier plate guided on guiding bars, this movablemould-carrying plate being displaceable by means of a hydraulic feedingand returning device, and being pro vided with anchoring rods, which, inthe closed position of the movable mould-carrier plate, extend into thestationary mould-carrier plate, and can be locked against the latter,one or more axially extensible pressure pads, for the production of themould-closing pressure, being arranged in the power linkage between themould parts, the mould-carrier plates and the anchoring rods.

Such die-casting machines as are described for instance in the UnitedStates patent specification No. 2,526,918 and in the Dutch patentspecification No. 83,969 mostly comprise a complicated and bulkystructure, which is conditioned by varoius rod-and-lever mechanisms,bearing devices for the feeding and returning cylinder, and holdingmeans for the anchoring rods, and also by auxiliary devices, and byspace obstructing pipes, located outside the machine, for the varioushydraulic pressure appliances. This always results in a comparativelygreat overall length of the machine, which leads to excessive lengths inthe case of relatively large machines, for the production of ratherheavy die castings; and such large machines, considered spatially, areno longer economically defensible.

The object of the present invention is to improve dieoasting machines inthis respect. The die-casting machine according to the invention isdistinguished 'by the fact that the anchoring rods are bored hollow, andare axially slidable upon the guiding bars, of the movable mouldcarrierplate, and that the guiding bars are provided with piston-likethickenings, the guiding bars and anchoring rods being constructed as adouble-acting hydraulically powered piston-and-cylinder system for thedisplacement of the movable mould-carrier plate.

By such a construction and arrangement of the anchoring rods and thedisplacing means for the movable mouldcarrier plate, the result isobtained in a simple manner that for the accommodation of these machineelements no further space is needed than that which must in any case beavailable for the opening of the mould when the height of the mouldassembly is greatest. Further-more, convenient accessibility to thespace between the mould parts is ensured, so that a casting can beeasily taken out of the mould, and the mould itself can also "be easilychanged.

For the accurate adjusting of the height of the mould assembly it hasbeen found advantageous that the anchoring rods should be secured in themovable mould-carrier plate in an axially adjustable manner. Accordingto a further feature of the invention the anchoring rods are secured byproviding them with external screw threads, while in the movablemould-carrier plate, corresponding adjusting nuts are rotatably mounted,and are secured against axial displacement. This provides thepossibility of continuously adjusting the height of the mould assemblyto any desired dimension, so that moulds of any thickness can be usedwithout distance pieces or the like hav- 3,093,863 Patented June 18,1963 ing to he slipped in between the mould and the mouldcarrier plate.Moreover the use of quite narrow pressure pads, with only quite a smallstroke, is hereby rendered possible, so that no special space isrequired for the accommodation of the pressure pads. Moreover by thisarrangement, the transmission linkage, operative in closing the mould,for the mould members, the mould-carrier plates and the anchoring rods,is restricted to the shortest possible dimension.

Furthermore a drive, common to all the adjusting nuts, and carried bythe movable mould-carrier plate, is advantageously provided, whereby aconvenient adjusting of the height of the mould assembly is ensured.

In order to prevent any turning of the anchoring rods themselves whenthey are being adjusted within the movable mouldcarrier plate, theanchoring rods may advantageously be each provided with a longitudinalgroove, in which there engages a slide-block embedded in the movablemould-carrier plate.

Further features are to be seen in the fact that in a manner known initself the pressure pads associated with the anchoring rods are arrangedbetween the stationary mould-carrier plate and the locking means thatarrest the anchoring rods, the clamping jaws of the locking means, whichare to engage in the anchoring rods, being displaceable in the axialdirection of the anchoring rods through a distance corresponding to thestroke of the pressure pads. The pressure pads are accordingly supportedupon a stationary part of the machine, so that the feed pipes of all thepressure appliances can likewise be stationarily passed through theinterior of the machine.

- There are therefore no obstructive flexible pipes to disturb theworking of the machine, whereby also the risks occasioned by flexiblepipes, for instance bursts or like interferences with working, areeliminated.

It is furthermore an advantage, for the quick working of the machine,that compression springs or like resilient elements are provided, whichact against the pressure pads, and which, when the pressure pads arerelieved of load, return not only the pressure pads themselves but alsothe clamping jaws of the locking means into the initial position, orretain them in their initial position. The advantage of this arrangementresides in the fact that after the relieving of the pressure padsnospecial manipulations or automatic controlling operations are necessary in order to bring the pressure pads and the clamping jaws back intothe initial position. The assurance is therefore also given that foreach working cycle of the machine the clamping jaws will be located inthe correct initial position that is necessary for a smooth and positiveor form-closed engagement, and that the full stroke of the pressure padswill be available each time for closing the mould.

One form of construction of a die-casting machine according to theinvention is illustrated by way of example in the accompanying drawings,so far as is necessary for the comprehension of the invention.

FIGURE 1 shows, partly in section, a die-casting machine according tothe invention, with the movable mouldcarrier plate in the closedposition;

FIGURE 2 is a side view of the closing frame or the fixed mould-carrierplate, likewise partly in section, and discloses the method of workingof the locking means; and

FIGURE 3 represents a plan of the stationary mouldcarrier plate, andshows the suspension of the guiding bars.

In FIGURE 1, by 1 is denoted plastifying and casting apparatusconstructed in any convenient manner, the injection cylinder 2 of whichengages through a front mouldcarrier plate 4, to open into thepouring-in bore of a mould, not shown. The mould-carrier plate 4 isfixedly mounted upon a base-plate 3, and constitutes the frontcross-piece of a mould-closing frame, which furthermore comprises a rearcross-piece 5, likewise stationary on the base-plate 3, and guiding bars6 connecting these two cross-pieces. The movable mould-carrier plate 7is slidably mounted upon the base-plate 3. For the ac curate parallelguidance thereof the guiding bars 6 are employed, of which four areprovided altogether. Anchoring rods, 8, which are each secured by oneend in the movable mould-carrier plate 7, are bored hollow, and areaxially slidable upon the guiding bars 6. At the tree ends of theanchoring rods 8, annular grooves 9 are provided, in which the clampingjaws 10 and 11 of a looking means, which are located opposite to oneanother in pairs, can engage.

The clamping jaws 10 and 11, which are carried, together with thelocking means, by the stationary mouldcarrier plate 4, aresemi-saucer-shaped, and can be reciprocated by means of twodouble-acting pistons 12 and 13, oppositely working, arranged in acommon cylinder 14. In this connection it is to be noted that theclamping jaws 10, and also the clamping jaws 11, of the two lockingdevices located horizontally side by side, which execute movements inthe same direction for the engagement and disengagement, are connectedwith one another by connecting bars :17, so that the clamping jawsconnected with one another always execute their closing and openingmovements jointly, although at times only one clamping jaw may beconnected by a piston rod 15 or 16 with the corresponding piston 12 or13. To enable the length of the connecting bars 17 to be accuratelyadjusted, a turnbuckle 18 is provided in each bar.

The anchoring rods 8, secured in the movable mouldcarrier plate 7 andslipped over the guiding bars 6, are sealed in an oiltight manner to thebars 6 by means of stutfing-boxes 20 let into them at their ends; and bypiston-like thickenings provided at 21 on the guiding bars 6, twohydraulic working spaces 22 and 23 are provided in the interior of theanchoring rods 8. When pressure oil or the like is introduced into thespace 22, the movable mould-carrier plate 7 is moved towards thestationary mould-carrier plate 4, that is to say; the mould is closed,whereas when pressure oil is forced into the space 23, the movablemould-carrier plate is pushed away from the stationary plate, that is,the mould is opened. The supplying of oil under pressure to the workingspaces 22 and 23 is preferably eiiected through ducts in the guidingbars 6.

To enable the anchoring rods 8 to be adjusted within the movablemould-carrier plate 7 when an alteration occurs in the height of themould assembly, the anchoring rods are provided, in their adjustmentregion, with an external sscrew thread 24, on to which an adjusting nut25 is screwed, which is rotatably suported in the movable mould-carrierplate 7. The adjusting nuts 25 are protected against axial movements bycollars turned thereon, which bear towards one side against the bearingbore, and, towards the other side, against rings 26, flanged on to themould-carrier plate 7. Upon the rims of the adjusting nuts 25,projecting from the bearing bores, toothed chain Wheels 27 are mountedfast, and around these runs an endless chain 28, which is common to allfour of the adjusting nuts 25. The chain 28 also runs over the pinion ofa drive 29, of an electric motor for example, which is mounted withinthe mould-carrier plate 7. By this drive the four adjusting nuts can allbe rotated simultaneously and uniformly. The adjusting nuts may ofcourse alternatively be driven through the medium of jointed spindles orthe like. In order to prevent the anchoring rods 8 turning when theadjusting nuts 25' are being actuated, a longitudinal groove 30 isformed in each anchoring rod, in which a slide-block 31, let into themouldcarrier plate 7, engages.

' clamping jaws 10 and 11 of the locking device.

For the production of the mould-closing pressure that is necessary forholding thermould parts together, four pressure pads 32 are provided,one of which is associated, in a manner known in itself, with each ofthe anchoring rods 8. The pressure pads 32 are made very flat, and areaccordingly of small thickness. They are of annular construction, andare secured to the stationary mould-carrier plate 4, and are arrangedbetween the latter and the The arrangement is such that the anchoringrods 8, which, in the closed position of the movable part of the mould,pene trate into the stationary mould-carrier plate 4, extend through theannular apertures of the pressure pads, to pass into the locking regionof the clamping jaws 10 and :11.

' to the movable mould-carrying plate 7, so that the movable mould partsecured thereto is pressed with great force against the fixed mouldpart. To open the mould, the pressure pads are relieved, and pressureliquid is admitted into the hydraulic working spaces 23 located in theanchoring rods 8. If the mould parts tend to stick together when themould is being opened, a high-pressure pump may be interposed in theadmission path for pressure liquid to the working spaces 23, to betransiently actuated.

Upon the stationary mould-carrier plate 4 are provided an upper and alower bearing yoke 34, which are secured to the carrier plate itselfwith strong screw connections 35. These bearing yokes 34 may in practicebe regarded as fixed parts of the mould-carrier plate 4, since in theirheads are lodged the bearing bores for the guiding bars 6, and in theirinterior are provided slideways 36 for guiding the clamping jaws 10 and11, as well as compression springs 37 or the like which co-operate withthe clamping jaws. The compression springs 37, which are inserted, inthe axial direction of the guiding bars 6 and of the anchoring rods 8,each between a pair of clamping jaws 10, 11 and one of the bearingyokes, act against the pressure pads 32, and are of such strength thatwhen the pressure pads are unloaded they push the clamping jaws 10 and1-1, and also the pressure pads themselves, into the zero or initialposition.

The machine here described and illustrated is one possibleconstructional example, to which the invention is not directlyrestricted. Modifications may on the contrary be made according torequirements. Thus the invention may be used not only for injectiondie-casting machines for the treatment of thermoplastic syntheticmaterials, but also tor pressing or casting machines for the treatmentof metals or of wood-fibre pulp.

I claim:

1. A die-casting machine for the production of molded bodies,particularly from thermo-plastic synthetic substances, comprising: astationary mold-carrier plate, adapted to carry one mold member, amovable mold-carrier plate, also adapted to carry one mold member,cylindrically bored anchoring rods each secured by one end to themovable mold-carrier plate and each extending into the stationarymold-carrier plate, means for locking the anchoring rods to thestationary mold-carrier plate, so as to hold the mold members in theclosed position, pressure pads provided between the said locking meansand the stationary mold-carrier plate and adapted to press the two moldmembers against one another when the anchoring rods are locked to thestationary mold-carrier plate, guiding bars for guiding the movablemold-carrier plate, each extending through the cylindrical bore of oneof the anchoring rods, and each supported at one end by the stationarymold-carrier plate, a stationary crosspiece supporting the other end ofeach of the guiding bars, pistons secured to the guiding bars within thecylindrical bores of the anchoring rods, stufling boxes closing the endsof the hollow anchoring rods, and means for admitting fluid underpressure to the cylindrical bores of the anchoring rods on either sideof the pistons so as to displace the anchoring rods, together with themovable mold-carrier plate and the mold member carried therebyrelatively to the guide bars, for the purpose of opening and closing themold.

2. A die-casting machine as claimed in claim 1, the anchoring rods beingsecured to the movable mold-carrier plate in an axially adjustablemanner, to allow for difierences in height of the mold assembly.

3. A die-casting machine as claimed in claim 1, further comprising:external screw threads on the anchoring rods, adjusting nuts engagingthese external screw threads, rotatably mounted in the movablemold-carrier plate, and means for securing the adjusting nuts againstaxial displacement.

4. A die-casting machine as claimed in claim 3, further comprising acommon drive, carried by the movable mold-carrier palte, forsimultaneously turning all the adjusting nuts.

5. A die-casting machine as claimed in claim 3, each E5 of the anchoringrods being formed with a longitudinal gnocve, and the machine furthercomprising for each anchoring rod a slide block, fixed in the movablemoldcarrier plate, and engaging in the said longitudinal groove, toprevent rotary motion of the anchoring rod.

6. A die-casting machine as claimed in claim 1, the means for lockingthe anchoring rods comprising: clamping jaws positively engaging theanchoring rods, the pressure pads being provided between the saidclamping jaws and the stationary mold carrier plate, and means foraxially extending the pressure pads and thereby increasing the thrust ofthe mold members against one another, after the mold has been closed byadmitting fluid under pressure to the appropriate side of the pistons.

7. A die casting machine as claimed in claim 6, further comprisingbearing yokes secured to the stationary mold-carrier plate, andcompression springs interposed between the pressure pads and the bearingyokes.

References (Cited in the file of this patent UNITED STATES PATENTS2,526,803 Carlson et al Oct. 24, 1950 2,862,238 Cuzzi Dec. 2, 19582,916,768 Quere et al. Dec. 15, 1959

1. A DIE-CASTING MACHINE FOR THE PRODUCTION OF MOLDED BODIES,PARTICULARLY FROM THERMO-PLASTIC SYNTHETIC SUBSTANCES, COMPRISING: ASTATIONARY MOLD-CARRIER PLATE, ADAPTED TO CARRY ONE MOLD MEMBER, AMOVABLE MOLD-CARRIER PLATE, ALSO ADAPTED TO CARRY ONE MOLD MEMBER,CYLINDRICALLY BORED ANCHORING RODS EACH SECURED BY ONE END TO THEMOVABLE MOLD-CARRIER PLATE AND EACH EXTENDING INTO THE STATIONARYMOLD-CARRIER PLATE, MEANS FOR LOCKING THE ANCHORING RODS TO THESTATIONARY MOLD-CARRIER PLATE, SO AS TO HOLD THE MOLD MEMBERS IN THECLOSED POSITION, PRESSURE PADS PROVIDED BETWEEN THE SAID LOCKING MEANSAND THE STATIONARY MOLD-CARRIER PLATE AND ADAPTED TO PRESS THE TWO MOLDMEMBERS AGAINST ONE ANOTHER WHEN THE ANCHORING RODS ARE LOCKED TO THESTATIONARY MOLD-CARRIER PLATE, GUIDING BARS FOR GUIDING THE MOVABLEMOLD-CARRIER PLATE, EACH EXTENDING THROUGH THE CYLINDRICAL BORE OF ONEOF THE ANCHORING RODS, AND EACH SUPPORTED AT ONE END BY THE STATIONARYMOLD-CARRIER PLATE, A STATIONARY CROSSPIECE SUPPORTING THE OTHER END OFEACH OF THE GUIDING BARS, PISTONS SECURED TO THE GUIDING BARS WITHIN THECYLINDRICAL BORES OF THE ANCHORING RODS, STUFFING BOXES CLOSING THE ENDSOF THE HOLLOW ANCHORING RODS, AND MEANS FOR ADMITTING FLUID UNDERPRESSURE TO THE CYLINDRICAL BORES OF THE ANCHORING RODS ON EITHER SIDEOF THE PISTONS SO AS TO DISPLACE THE ANCHORING RODS, TOGETHER WITH THEMOVABLE MOLD-CARRIER PLATE AND THE MOLD MEMBER CARRIED THEREBYRELATIVELY TO THE GUIDE BARS, FOR THE PURPOSE OF OPENING AND CLOSING THEMOLD.